1. Technical Field
The present invention relates to a headlight provided to a vehicle such as an automobile, and particularly relates to a vehicle headlight with which visibility of a target, upon passing by the target adjacent to a driving lane of a vehicle, is improved.
2. Related Art
A headlight of a vehicle such as an automobile projects light emitted from a light source such as, for instance, an incandescent light bulb, discharge lamp, and LED with a projection optical system such as a projector and a reflective optical system such as a reflector.
With such a headlight, switching is possible between a driving beam (high beam) for use during normal driving and a passing beam (low beam) for use when passing an oncoming vehicle.
In order to prevent glare that dazzles an oncoming driver, a cutoff line is formed in a predetermined range at the upper edge of a light distribution pattern for the passing beam, such that light is substantially not radiated above the cutoff line.
In such a headlight, it is known that a desired light distribution pattern is formed through collaborative use of a plurality of light sources or optical systems.
For instance, Japanese Unexamined Patent Application Publication (JP-A) No. 2011-3515 describes that a main light distribution pattern or the like having a cutoff line is formed by a projector unit and a diffused light distribution pattern is formed by a reflector unit.
JP-A No. 2011-161035 describes that a part of a beam emitted by a light source of a projector unit is guided to a reflector by a mirror member to illuminate a shoulder or the like on the driving lane side.
JP-A No. 2001-195910 describes a technique in which an auxiliary light distribution pattern for a passing beam from a projector unit is formed by an auxiliary reflector.
A general light distribution pattern for a passing beam enables a target such as a pedestrian and bicycle beside a driving lane to be illuminated, in the case where the distance from a vehicle is sufficiently far. However, when the vehicle and the pedestrian or the like are in proximity, the pedestrian or the like falls outside the light distribution pattern. Therefore, there have been cases where the pedestrian or the like is not sufficiently visible upon passing, rendering it difficult to perform an appropriate check on whether the path is clear or the like.